Electromechanical relay

ABSTRACT

This invention relates to a electromechanical relay having one or more double pole double throw switching subassemblies in a &#39;&#39;&#39;&#39;dual-in-line&#39;&#39;&#39;&#39; package. More specifically, the relay in its simplest form contains a motor subassembly driving a overlying armature which in turn moves a double leaf switch arm from one contact to another. The double leaf switch arm, pins, contacts, armature dampener arms and coil connections are stamped and formed from a single coplanar sheet of conductive material in the orientation of that of their positions in the assembled relay.

Sept. 3, 1974 United States Patent I 1 Cassarly et al.

7/1965 Moore 335/187 ELECTROMECHANICAL RELAY Youngfleish, both of Harrisburg, all of Pa.

[73] Assignee: AMP Incorporated, Harrisburg, Pa.

[22] Filed:

[75] Inventors: James William Cassarly,

Lewisberry; Norwood Claude Graeft, Harrisburg; Dean Roosevelt Hooper, Jr., Middletown; William Vito Panza, Palmyra; Wilmer Lee Sheesley; Frank Christian 1973 This invention relates to a electromechanical relay having one or more double pole double throw switchdual-in-line package. More n its simplest form contains a motor'subassembly driving a overlying armature which aw .mm m am mt mm 33 w g 1 1 Appl. No.: 414,464

in turn moves a double leaf switch arm from one contact to anotherv The double leaf switch arm, pins,

contacts, armature dampener arms and coil connections are stamped and formed from a single coplanar sheet of conductive material in the orientation of that of their positions in the assembled relay.

References Cited UNITED STATES PATENTS 3,141,939 7/1964 335/202 2 Claims, 7 Drawing Figures PATENTEDSEP 31914 SHEEI 20$ 4 succraurd Pmmmszv sum ELECTROMECHANICAL RELAY BACKGROUND OF THE INVENTION large number of diverse parts wherein the mechanical and electrical connections thereinbetween require cost producing assembly operations.

Further such relays have finished package sizes which make them unsuited for use on printed circuit boards where several switching functions are needed.

Accordingly the present invention provides an electromechanical relay having a small number of parts within a relatively small package wherein the assembly operations are minimal due to the preoriented contact and spring elements of the leadframe stamping.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded view of an electromechanical relay constructed in accordance with the present invention;

FIG. 2 is an enlarged exploded view of the motor assembly of the relay in FIG. 1;

FIG. 3a illustrates the stamped lead frame of the relay in FIG. 1 and FIG. 3b illustrates the same lead frame after is has been formed and the carrier strips removed;

FIGS. 4a and 4b are a view showing a method of providing overlap between the contact members; and

FIG. 5 is a cross-sectional view ofan assembled relay of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT The exploded view of the electromechanical relay in FIG. 1, constructed in accordance with the present invention, dramatically illustrates its simplicity and small number of parts. The relay may be grouped into three assemblies: the housing, the motor, and the lead frame. The housing assembly consists of a base member and cover member 12 with its lids. The motor assembly consists of an electromagnetic. coil 14 and armature 16 The lead frame 18 contains a plurality of contacts, switch arms, pins, coil connections and armature dampeners.

Base member 10 may be molded, preferably using glass filled nylon as the molding material. It contains two compartments 20 separated by a wall 24. A sidewall in each compartment is built out slightly as indicated generally by reference number 26. On the same sidewall there is a vertical, elongated rectangular post 28, integral with the sidewall, which extends upwardly from the compartment base as seen in FIG. 5. The top surface 30 along with the surfaces on the end and center walls provides a support and exact positioning for the motor assembly.

The outside surfaces of the sidewalls contain eight channels 32 which receive the leg portions of lead frame 18. The four corners of the base member 10 extend above the top surface of the sidewalls to provide spacing between the lead frame and cover member 12.

FIG. 2 is an exploded view of the motor assembly before it is put together. The windings have been omitted to reveal the shape of the bobbin. These windings however can be seen in FIGS. 1 and 5 wherein they are designated by the reference numeral 34.

As noted above, the motor assembly consists of the electromagnetic coil subassembly 14 and armature subassembly 16. In turn the electromagnetic coil subassembly consists of a bobbin 40, the aforementioned windings 34 (FIGS. 1 and 5) a U-shaped metallic core 42, and a pair of coil contacts 44. The armature subassembly consists of an armature 46 and a carrier, camming and pivoting device, hereinafter refered to as simply the pivot 48.

As the elements 4248 are housed or carried by bobbin 40, they will be described first.

The U-shaped metallic core 42, blanked out from a coplanar strip of metal such as annealed nickel-iron, has a pivoting leg 50, a bight 52 and an energizing leg 54. The top surface of the pivoting leg is beveled on one side to provide a pivoting edge 56.

The energizing leg 54 is shown in FIG. 2 as being bent away from a plane parallel to leg 50. This is done to allow the core to be slipped onto bobbin'40 at which time the energizing leg is bent into the shape seen in FIG. 5; i.e., parallel to leg 50. The upper portion of leg 54 has been laterally expanded to provide a wider contact surface designated by the reference numeral 58. This flat, horizontal surface is more clearly seen in FIGS. 1 and 5. The underside of surface 58 is beveled to fit onto a complimentary surface on the bobbin, again as seen clearly in FIG. 5. In order to provide some appreciation for the dimensions involved in a production model of this novel electromechanical relay, the above-described core has a maximum overall height of 0.378 inches and a overall width when assembled in the bobbin of 0.136 of an inch. The thickness of the metal stock is 0.025 t 0.0005 inches.

The two coil contacts 44 are stamped out of flat wire stock of phosphorus bronze or the like. A short portion of one end is bent degrees and contains a number of beveled serrations 60. These serrations frictionally hold the contacts in the bobbin. Preferably the contacts are plated with gold to a thickness of about 0.000030 inches. The thickness of the flattened stock in the aforementioned production model is about 0.010 inches.

Armature 46 of the armature subassembly is blanked out from strip stock of metal such-as annealed nickeliron. The width of the forward end 62, has been reduced to accommodate two upright posts on the bobbin. Just behind the tab-like forward end is a round stud-receiving hole 64. In the mentioned production model, the armature 46 has a total length of 0.235 inches, an overall width of 0.235 inches and a thickness of about 0.020 inches. The lower surface of the armature must be polished but the upper surface is preferably left rough so as to provide a better adhesion surface.

The pivot 48 is molded from NYLON or other such insulating material. Jutting out from either sidewall at the pivots rearward end are pivoting shafts 66. Two dampening lobes 68 arise above the upper surface of the pivot and extend along either edge. Note that the highest point of the lobes are at the forward side (towards the reader) of the shafts; i.e., the lobes are offset forwardly of the shafts.

A cam 70 is located on the forward edge of the pivot and extends parallel thereto.

The underside of the pivot is recessed to receive armature 46 as shown in FIG. 1. A downward depending stud 72 is provided to position the armature in the pivot. The two elements of the armature subassembly are fastened together by adhesive.

Bobbin 40 is a unitary structure molded from a glass filled nylon. It consists of three distinct features, a upper flange 74, a lower flange 76 and a hollow, rectangular wire-receiving support 78 joining the two flanges.

The interior surfaces of both flanges are flat and parallel each other.

The outer surface of upper flange 74 is bounded on either side by sidewalls 80. A inside-facing slot 82 is located in each sidewall. The forward portion 83 of the surface is beveled downwardly and'outwardly. At the forward edge and spaced between the two sidewalls are a pair of upstanding preload posts 84. The rearward portion 85 of the surface is likewise beveled to form a surface inclined downwardly and outwardly.

Intermediate the two beveled portions, the outer surface of upper flange 74 is flat.

At the rearward face of each sidewall 80 is a horizontal slot 86 into which the serrated end portion of contacts 44 are positioned.

The forward edge of lower flange 76 contains a groove 88. The rearward edge also contains a groove 90. Both rearward corners are notched as generally indicated by the reference numeral 92.

The outer surface of the lower flange is recessed as can be seen in FIG. 5. This recess provides clearance for bight 52 of the metallic core.

A rectangular passageway 94 passes through support 78 and opens out on both outer surfaces of upper and lower flanges 7476.-As'with any other electromagnetic coil, magnet wire is wound around support 78. A preferred wire in this application is a No. 40 magnetic wire with polyurethane insulation.

With reference to FIGS. 1 and S as well as FIG. 2, the various parts of the motor assembly are assembled on the bobbin to provide a compact unit. The pivoting leg 50 passes up through passageway 94 with its top surface and pivoting edge 56 projecting above the outer surface of the upper flange. The pivoting edge faces toward the preloadposts 84. The energizing leg 54 extends up the rear of bobbin 40 with beveled underside of contact surface 58 resting on the rearward beveled portion of the outer surface.

The segmented ends of contacts 44 are pushed into slots 86 on sidewalls 80 and the long portions are bent down with the other end being received in notches 92. An end of the windings 34 is wrapped around each contact and soldered or otherwise secured thereto.

Preferably the armature subassembly is placed on the bobbin after the bobbin has been placed in a compartment 20. j

The term lead frame" as used herein will apply both to the stamped frame illustrated in FIG. 3a and the formed frame illustrated in FIGS. 1 and 3b (sans the side and end support strips) and FIGS. 4a and 4b. The

lead frame is stamped and formed from a coplanar sheet or strip of conductive material such as phosphorus bronze. It preferably is plated with gold along the narrow band which will become the points of physical contacts. The thickness of the material in the aforementioned production model is about 0.400 inches.

As shown in FIG. 3a, lead frame l8 includes a top side strip a, a bottom side strip 100b, a left end strip 102L and a right end strip l02r. Within the surrounding strips are sixteen contact members, some of which are specifically pointed out by the capital letters CM. Eight of the members are integral with and project inwardly from side strip 100a and the other eight are integral with and project inwardly from side strip 100b.

The l6 contact members are arranged into two sets each of which contains a double pole double throw switch, two dampening arms and two coil contact arms. One such set is to the right and the other is to the left of the dashed line bisecting the frame and marked by the reference numeral 104. It is to be observed, particularly in FIG. 3b, that each set is identical to each other but are orientated 180 as is conventional in relays having two double pole-double throw switches. Since the sets are identical only the right hand set will be described although the corresponding member in the other set will carry the same reference'numeral.

Each contact member CM has two distinct features; a leg and a arm. The leg is or becomes the vertical part of the member and the arm is or becomes the horizontal part. Obviously, before forming, the entire frame is on the same plane as seen in FIG. 3a.

Specifically referring to FIG. 3b, the leg consists of a pin 106 and a support portion 108. The pin is that part of the relay which is inserted into spaced holes in a printed circuit board (not shown) and makes electrical contact with the circuits thereon.

The juncture between pin 106 and support portion 108 forms a downwardly facing shoulder 110 which permits the mounting of an assembled relay above the printed circuit board surface by a predetermined distance. Another term for this feature is standoff.

Support portion 108 lays in groove 32 on base member 10 and is preferably secured there with epoxy. Each support 108 contains inwardly, depressed areas 112 on each side. These areas allow a higher concentration of epoxy at those points and thus provide additional adhesive retention of the leg to the base member.

The arm is at the other end of the contact member and begins at the point where the contact member is bent 90. With reference to FIGS. 3a and 3b, attention is again drawn to the fact that each set contains eight contact members, four projecting inwardly from one side, the other four projecting inwardly from an opposite side. In this manner the inner ends of the contact members (as opposed to the outer ends which comprise pins 106) face each other and as FIG. 3a shows they are, before forming, all in the same plane; i.e., no over- I lapping.

the path for current to the motor assembly from the PC board. The inner-most branches are the dampening arms 116. These arms are bent downward'from the horizontal and ride on lobes 68. They perform two services; first, they prevent armature bounce, i.e., absent these restraints, the armature subassembly would flop up and down after the coil was de-energized. This bounce can cause the cam on the pivot to move the movable contact arm off the normally closed contact. The second function is that the arm, in cooperation with the off-center lobes, biases the armature subassembly downwardly toward the forward portion 83 on bobbin 40 when the coil is not energized. This too prevents accidental movement of the movable contact arm.

The two inside arms comprise the two movable contact arms 118. These arms might also be referred to as switch arms. As the drawings show, the two arms are the mirror image of each other. Near the inner end; the arms are formed into two fingers. The outer-most finger is off-set and downwardly displaced from the arm proper. As this finger contacts the normally open fixed contact, it is referred to as the normally opened moving contact 120.

The inner-most finger; ie. the continuation of the arm proper, is referred to as the normally closed moving contact 122 since it contacts the normally closed fixed contact.

On the opposite side of the aforementioned arms, and projecting inwardly from side strip 100a are the four fixed contact arms. The outer-most arms comprise the normally opened fixed contacts 124. These contacts, via the rectangular path in which they are formed provides to the relay the benefits of a long spring member without the drawback of having to provide a long space. Further the effective increase in beam length provides a significant amount of torsional deflection as well as increased bending deflection. After forming the entire arm is bent downwardly to a predetermined distance. Upon assembly into the relay, these fixed contacts 124 abutt the aforementioned preload posts 84. These posts via their height, deflect the arms back to a horizontal position thereby loading the arms with a force which acts on the moving contact 120 during operation of the relay. This preload force eliminates the need to move a member through a specific distance in order to build up the force to a proper value.

The inner-most arms comprise the normally closed fixed contacts 126.

As is apparent from FIGS. 3a and 3b, there is a change in the lead frame from one where the contact members are all in the same plane as in FIG. 3a to where some of the members overlay other members as shown in FIG. 3b. A preferred method for achieving this result is shown in FIGS. 4a and 4b.

FIG. 4a shows part of the lead frame 18 of FIG. 3a after it has been formed into the U-shaped configuration. Note that the one movable arm, comprising moving contacts 120-122, is spaced away from fixed contacts 124-126. To interpose or overlay these contacts, a jogging or off-set forming process is performed on carrier end strips 102. A mid-section of each end strip is off-set as shown in FIG. 4b. The structural change is denoted by the reference numeral 128. Obviously the jogging reduces the width between the sides of the lead frame and causes the fixed and movable contacts to overlap one another the required distance. The overlap is clearly seen between the normally closed fixed contact 126 and normally closed movable contact 122 in FIG. 4b. The proper configuration is that movable contact 120 is below fixed contact 124 and movable contact 122 is above fixed contact 126.

In assembling the electromechanical relay constructed in accordance to the present invention, the many novel features therein provide a accurate, balanced and high performing result without the need for highly skilled workmen or test equipment notwithstanding the tiny sizes involved.

After bobbin is wound with magnet wire 34, coil contacts 44 are secured to the bobbin and lead wires are wrapped around and fastened thereto. This may be seen in FIG. 1, the wrapping designated by reference numeral 130.

Metallic core 42 is placed on bobbin 40 by inserting leg up through passageway 94 and crimping or bending leg 54 up against the bobbin so that the contact surface 58 overlies rearwardly beveled portion 85. The electromagnetic coil subassembly 14 is now placed into a compartment 20 and preferably secured therein with an adhesive. As FIG. 5 shows the bight 52 and lower flange 76 is supported by the base 132 of the compartment and the upper flange 74 rests on post 28.

Armature subassembly 16 is now placed on top of the coil subassembly 14 with shafts 66 in slots 82. Armature 46 rests on the top of metallic core leg 50. The 10- cations of the slots predetermines the location of the armature subassembly.

After another coil subassembly l4 and armature subassembly 16 has been mounted in a like manner in the adjacent compartment 20, the formed U-shaped lead frame 18 with the carrier side and end strips -102 attached is placed onto the base member 10 so that the support portion 108 of the contact members fit into channels 32, the pins 106 depend below the base member 10 and the arms, with the exception of the connectors 114, span the open conpartments 20. The dampening arms 116 abutt lobes 68 and, as FIG. 5 shows, biases the armature subassembly l6 downwardly so that armature 46 rests on forward beveled portion 83. The movable contacts 122 rest on top of fixed contacts 126 while movable contacts are spaced below fixed contacts 124.

Subsequent to attaching the lead frame onto base member 10, cover member 12 sans its lids 134 is slid down over the base member and secured thereto by adhesive. Side and end strips 100-102 are now removed from the lead frame thereby isolating each contact member. The relay is now ready for testing and adjusting of the movable contact arms through the openings 136 is needed. Upon satisfactory tests, the lids are placed onto the cover and fastened thereto by adhesive.

In operation, the relay described above provides a current path through the movable contact arms and the fixed contacts; without coil energizing, through the normally closed contacts. Upon the coil being energized the armature is drawn toward contact surface 58 on the metallic core by magnetic forces. As the armature subassembly pivots, cam 70 engages the movable contact arms and lifts them up so that the electrical contact between fixed contacts 126 and movable contacts 122 is broken and electrical contact between fixed contact 124 and movable contact 120 is made. When the coil is de-energized, the armature subassembly is rotated back to the position shown in FIG. by the biasing force of dampening arms 116.

The foregoing detailed description has been given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, as some modifications will be obvious to those skilled in the art.

What is claimed is: 1. An electromechanical relay which comprises: a. a base member having a compartment;

b. a electromagnetic coil subassembly positioned in i. first arm providing a first fixed contact describing a generally rectangular path,

ii. second arm providing a second fixed contact positioned alongside the first fixed contact and electrically isolated therefrom,

iii. a third arm providing a movable arm and positioned opposite said fixed contacts, the end of said third arm being bifurcated into two movable contacts with one such contact overlapping said second fixed contact and the other such contact being off-set and downwardly displaced and underlying said first fixed contact;

iv. a fourth arm adapted to provide a current path to said electromagnetic coil whereby when said coil is energized, magnetic force causes said armature subassembly to rotate about with said camming means engaging said third arm and moving it from one fixed contact to another fixed contact; and

e. insulating cover means for covering said compartment.

2. An electromechanical relay which comprises:

a. a insulating housing having a compartment therein,

b. means for switching an electrical current back and forth from one circuit to another, said means including a plurality of contact members of which, i. a first member includes an arm fixed in space over the compartment, said arm providing a first fixed contact,

ii. a second member includes an arm fixed in space over the compartment and positioned generally parallel to the arm of the first member, said arm of the second member providing a second fixed contact,

iii. a third member, located on the opposite side of the compartment from the first and second members, includes a movable arm extending across the compartment and providing a movable contact, the end of said arm being formed intotwo spaced-apart parallel fingers with the first finger being the axially extension of the arm and the second finger being offset laterally and displaced downwardly relative to the arm, the first finger overlapping and engageable with the first fixed contact and the second finger underlapping and engageable with the second fixed contact, and iv. a fourth member includes a arm adapted to provide an electrical path to a coil, all of the aforementioned contact members each having as an integral part thereof, a leg which extends alongside the housing and depends therefrom, said legs adapted for insertion into printed circuit board receptacles for engagement with electrical circuits thereon; and c. an electromagnetic coil operating an armature pivotally mounted on top thereof, said coil positioned in the compartment beneath the contact members with the armature engageable with the movable contact so that as the coil is energized the armature moves the movable contact removing one finger from one fixed contact and engaging the other finger to the other fixed contact and thereby switching an electrical current which may pass through said contact members from one fixed contact to the other. 

1. An electromechanical relay which comprises: a. a base member having a compartment; b. a electromagnetic coil subassembly positioned in the compartment; c. an armature subassembly pivotally mounted on top of said electromagnetic coil subassembly, said armature subassembly having camming means thereon; d. a plurality of contact members having legs thereon extending down and below said base member and having a plurality of arms extending across said compartment from either side, said arms including, i. first arm providing a first fixed contact describing a generally rectangular path, ii. second arm providing a second fixed contact positioned alongside the first fixed contact and electrically isolated therefrom, iii. a third arm providing a movable arm and positioned opposite said fixed contacts, the end of said third arm being bifurcated into two movable contacts with one such contact overlapping said second fixed contact and the other such contact being off-set and downwardly displaced and underlying said first fixed contact; iv. a fourth arm adapted to provide a current path to said electromagnetic coil whereby when said coil is energized, magnetic force causes said armature subassembly to rotate about with said camming means engaging said third arm and moving it from one fixed contact to another fixed contact; and e. insulating cover means for covering said compartment.
 2. An electromechanical relay which comprises: a. a insulating housing having a compartment therein, b. means for switching an electrical current back and forth from one circuit to another, said means including a plurality of contact members of which, i. a first member includes an arm fixed in space over the compartment, said arm providing a first fixed contact, ii. a second member includes an arm fixed in space over the compartment and positioned generally parallel to the arm of the first member, said arm of the second member providing a second fixed contAct, iii. a third member, located on the opposite side of the compartment from the first and second members, includes a movable arm extending across the compartment and providing a movable contact, the end of said arm being formed into two spaced-apart parallel fingers with the first finger being the axially extension of the arm and the second finger being offset laterally and displaced downwardly relative to the arm, the first finger overlapping and engageable with the first fixed contact and the second finger underlapping and engageable with the second fixed contact, and iv. a fourth member includes a arm adapted to provide an electrical path to a coil, all of the aforementioned contact members each having as an integral part thereof, a leg which extends alongside the housing and depends therefrom, said legs adapted for insertion into printed circuit board receptacles for engagement with electrical circuits thereon; and c. an electromagnetic coil operating an armature pivotally mounted on top thereof, said coil positioned in the compartment beneath the contact members with the armature engageable with the movable contact so that as the coil is energized the armature moves the movable contact removing one finger from one fixed contact and engaging the other finger to the other fixed contact and thereby switching an electrical current which may pass through said contact members from one fixed contact to the other. 